1. Field of the Invention
The field of this invention is internal combustion engines, of both spark ignition and compression ignition type, and particularly such engines utilizing stratified air fuel mixtures at the engine intake manifold and intake valve.
2. Description of the Prior Art
A description of several prior art stratified air fuel mixtures and their use at engine intake is contained in reference A, U.S. Pat. No. 4,147,137, and this descriptive material is incorporated herein by reference thereto. A brief summary of portions of this referenced subject matter particularly relevant to this patent application follows. Three types of intake air fuel mixture stratification are described therein: two barrel carburetor type; injected liquid spray type; multiregional type. Additionally, it is shown therein that stratification created at engine intake survives at least until combustion and that extremely lean air fuel ratio mixtures can be compression ignited. Further, it is shown therein that the noise consequent upon the compression igniting of near stoichiometric air fuel mixture regions can be reduced by making such regions individually of small volume, by scattering such regions about in amongst other kinds of regions, and by arranging that large differences exist in the compression ignition time delay characteristics of those regions which are compression ignited. The engine intake stratifier described and claimed in reference A creates a multiregional stratified air fuel mixture at engine intake by use of a stratifier valve with several separate air fuel mixture creating channels in combination with other elements. An engine intake mixture possessing multiregional stratification consists of many individual regions, each such region being small and essentially of uniform mixture within itself, and adjacent regions differ as to the air fuel ratio or the fuel type or both. The volume of individual regions in the multiregional air fuel mixture can be reduced by increasing the port indexing rate of the stratifier valve and the extent of scattering of one particular type of air fuel mixture region can be increased by increasing the number of active ports and separate air fuel mixture creating channels used by the stratifier valve. Differences in compression ignition time delay characteristics can be made larger by using different kinds of fuels and/or different air fuel mixture ratios as between the several separate air fuel mixture creating channels. In these ways the compression ignition noise level can be reduced when multiregional engine intake stratification is used as described in reference A.
It is a disadvantage of the engine intake stratifier of reference A that to accomplish large reductions of engine noise due to compression ignition requires the stratifier valve to become more complex mechanically, the number of separate air fuel mixing channels to become large, and the number of different fuels and hence fuel tanks to become large, and thus the complexity and cost of the engine system are increased as noise level is reduced.
Many of the beneficial objects made available by use of multiregional intake stratification result from the fact that compression ignition can then be used without excess engine noise. Because compression ignition is intended to occur, higher engine compression ratios are used with consequently increased engine efficiency. Additionally, engine supercharge can be used to reduce engine size, weight and friction power loss. Because very lean and fully evaporated mixtures can be used, the exhaust emissions of undesireable smog-forming materials and of smoke can be reduced as compared to conventional internal combustion engines. These and other beneficial objects made available by use of multiregional stratified engine intake mixtures are described in reference A.
Additional description of prior art stratified air fuel mixtures at engine intake and methods for creating such mixtures are contained in U.S. Pat. No. 4,205,647 and this description of prior art is incorporated herein by reference thereto.
The devices of this invention are used in combination with an internal combustion engine. The term "internal combustion engine" is used herein and in the claims to mean the known combination of elements comprising cylinders, cylinder heads, pistons operative within said cylinders and connected to a crankshaft via connecting rods, valves and valve actuating means or cylinder ports, lubricating system, cooling system ignition system if needed, flywheels, starting system, fuel supply system, fuel-air mixing system, intake pipes and exhaust pipes, torque control system, etc. as necessary for the proper operation of said internal combustion engine. The term "internal combustion engine" is used hereinafter and in the claims to include also the known combination as described above but wherein the cylinders, cylinder heads, pistons operative within said cylinders and connected to a crankshaft via connecting rods, valves and valve actuating means or cylinder ports, are replaced by a rotary engine mechanism combination, comprising a housing with a cavity therein, and plates to enclose the cavity, a rotor operative within said cavity and sealing off separate compartments within said cavity and connecting directly or by gears to an output shaft, ports in said housing for intake and exhaust. The term "internal combustion engine" as used herein includes atmospherically aspirated internal combustion engines as well as supercharged internal combustion engines using turbochargers or other types of intake air compressors. The term "internal combustion engine" is used herein and in the claims to mean internal combustion engines of the spark ignition type, of the compression ignition type and of the type using both spark and compression ignition.
The term, internal combustion engine mechanism, is used hereinafter and in the claims to mean all those portions of an internal combustion engine, as defined hereinabove, except the fuel air mixing system and the torque control system.